Cab Design Questions ?

Help Anyone!!
I want to make use of an old JBL D-140 that I have laying around the house.
I have a 2-12 Fender Bassman cabinet also with JBL's, that I think would be an interseting mate to the 12s for bass use.
I really don't know beans about cabinet design and would most likely struggle thru any design programs any of you might give me links to.
I have a Bag End S15D. (That I love!!)
Would it work to simply reverse engineer the Bag end specs for the new cabinet and still have the JBL perform at it's best?
Has anyone out there done this with good results?
I was also looking at simply cutting the Bassman dimensions in half, just large enough to fit the JBL into.

I don't have the T/S data for a driver that old. I remember using D140F bass drivers when I was a kid in the early 1960s.

Using the obsolete K140 as a guide, a wild guess would be 2 cubic feet tuned at 30 Hz. The current production E140 is 0.94 cubic feet tuned at 73 Hz. Not really very good for electric bass.

You can be pretty safe using a sealed box, 1.0 to 1.6 cubic feet. Without actually measuring the T/S parameters of the D140, it's really just a guess. A sealed box sounds a lot better than a vented box does when you are guessing.